---+ Security Alert: Code injection vulnerability in MAKETEXT macro, Denial of Service vulnerability in MAKETEXT macro. This advisory alerts you of a potential security issue with your Foswiki installation. A vulnerability has been reported against the core Perl module CPAN:Locale::Maketext, which Foswiki uses to provide translations when {UserInterfaceInternationalization} is enabled in the configuration. Because of this vulnerability it may be possible for a user to run arbitrary shell commands and code on the server through a crafted %MAKETEXT% macro. If your wiki allows commenting by users without first logging in, then it may be possible for such an anonymous user to exploit this vulnerability. ---++ Severity Level Severity 1 issue: The web server can be compromised The severity level was assigned by the Foswiki Community.SecurityTaskTeam as documented in Development.SecurityAlertProcess ---++ Vulnerable Software Versions All released versions of Foswiki are vulnerable to these issues - Foswiki 1.0.0 - 1.0.10 - Foswiki 1.1.0 - 1.1.6 ---++ MITRE Name for this Vulnerability The Common Vulnerabilities and Exposures project has assigned the name CVE-2012-6329 to this vulnerability, see http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-6329 CVE-2012-6330 was assigned to the Denial of Service vulnerability, see http://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2012-6330 ---++ Attack Vectors Editing wiki pages and HTTP POST requests towards a Foswiki server with enabled localization (typically port 80/TCP). Typically, prior authentication is necessary. A crafted %MAKETEXT{}% macro will pass through strings to Locale::Maketext where they are executed under the control of the CGI user on the server. Any user with the authority to edit a topic, comment on a topic, or execute the Foswiki rendering code (eg. The RenderPlugin) can take advantage of the vulnerability. (CVE-2012-6329) A crafted %MAKETEXT{}% macro will consume large amounts of memory and exhaust swap space. (CVE-2012-6330) ---++ Impact Arbitrary code execution on the server can expose the file system. A second less severe Denial of Service vulnerability is also addressed by this alert. ---++ Details A crafted %MAKETEXT{}% macro can cause multiple issues: * Execute arbitrary code on the server by passing unsanitized strings to Locale::Maketext. * Consume memory and swap space resulting in potential lockup or crash due to %<nop>MAKETEXT{}% not validating the parameter numbers supplied in the [_nnn] tokens. * Cause an exception within Foswiki, also due to invalid parameters in [_nnn] tokens ---++ Countermeasures One of the following should be done as soon as possible. * Manually Apply hotfix (see patch below). __or__ * Apply the [[Extensions.PatchItem12285Contrib][http://foswiki.org/Extensions/PatchItem12285Contrib]] to your Foswiki 1.1.x system (Does not apply to Foswiki 1.0.x) __or__ * Disable {UserInerfaceInternationalization} in your LocalSite.cfg _(Does not protect against [[SecurityAlert-CVE-2012-6330]])_ __or__ * The foswiki debian package has already been updated with the hotfix - use your preferred package management tool to update to foswiki 1.1.6-2 In addition, CPAN:Locale::Maketext version 1.23 or newer should be installed. Upgrade to the latest patched production Download.FoswikiRelease01x01x07 once released *The Foswiki patch fixes other issues with the %MAKETEXT% macro beyond the code execution issue. Even if the new Locale::Maketext is installed, it is strongly recommended to apply the Foswiki patch.* ---++ Hotfix for Foswiki Release 1.1.0 - 1.1.6 Install http://foswiki.org/Extensions.PatchItem12285Contrib and verify that the patch has been applied to lib/Foswiki/Macros/MAKETEXT.pm. The extension will attempt to apply two patches, and should report that 1 file was patched. Only one of the patches will match your system. This patch fixes both CVE-2012-6329 CVE-2012-6330. Running Post-install exit for PatchItem12285Contrib... Processing /var/www/data/Foswiki-1.1.1/working/configure/patch/Item12285-001.patch ... MD5 Matched - applying patch version Foswiki 1.1.0 - 1.1.2. Update successful for /var/www/data/Foswiki-1.1.0/lib/Foswiki/Macros/MAKETEXT.pm . 1 file patched ... Processing /var/www/data/Foswiki-1.1.1/working/configure/patch/Item12285-002.patch ... No files matched patch signatures On a properly patched system, %MAKETEXT{" [_101] "}% should return an error. Excessive parameter number 101, MAKETEXT rejected. Note that this Contrib will also install the Extensions.PatchFoswikiContrib as a prerequisite. PatchFoswikiContrib patches the Extensions installer to accept the new style version strings used for modules released as of 1.1.6. ---++ Hotfix for Foswiki Archived Release 1.0.0-1.0.10 This patch fixes both [[SecurityAlert-CVE-2012-6329]] and [[SecurityAlert-CVE-2012-6330]]. This release should be manually patched. In Foswiki.pm, in the sub MAKETEXT ============ vvv CUT vvv ============= --- Foswiki.pm 2010-01-17 09:16:20.000000000 -0500 +++ Foswiki.pm 2012-12-10 10:06:37.389129654 -0500 @@ -4200,6 +4200,9 @@ $str =~ s/~\[(\*,\_(\d+),[^,]+(,([^,]+))?)~\]/ $max = $2 if ($2 > $max); "[$1]"/ge; + return "Illegal parameter number" if ($max > 100); + $str =~ s#\\#\\\\#g; + # get the args to be interpolated. my $argsStr = $params->{args} || ""; ============ ---CUT--- ============= ---++ Manual patch for Foswiki Release 1.1.0 -> 1.1.6 Installing the Extensions.PatchItem12285Contrib is the best way to patch your system - you can however see the patch we apply here. This patch fixes both [[SecurityAlert-CVE-2012-6329]] and [[SecurityAlert-CVE-2012-6330]]: ============ vvv CUT vvv ============= --- lib/Foswiki/Macros/MAKETEXT.pm 2012-12-11 10:51:12.959268829 -0500 +++ lib/Foswiki/Macros/MAKETEXT.pm 2012-12-11 10:37:31.674486503 -0500 @@ -4,9 +4,19 @@ use strict; use warnings; +use Locale::Maketext; +my $escape = + ( $Foswiki::cfg{UserInterfaceInternationalisation} + && $Locale::Maketext::VERSION + && $Locale::Maketext::VERSION < 1.23 ); + sub MAKETEXT { my ( $this, $params ) = @_; + my $max; + my $min; + my $param_error; + my $str = $params->{_DEFAULT} || $params->{string} || ""; return "" unless $str; @@ -18,15 +28,22 @@ $str =~ s/~~\[/~[/g; $str =~ s/~~\]/~]/g; + $max = 0; + $min = 1; + $param_error = 0; + # unescape parameters and calculate highest parameter number: - my $max = 0; - $str =~ s/~\[(\_(\d+))~\]/ $max = $2 if ($2 > $max); "[$1]"/ge; + $str =~ s/~\[(\_(\d+))~\]/_validate($1, $2, $max, $min, $param_error)/ge; $str =~ -s/~\[(\*,\_(\d+),[^,]+(,([^,]+))?)~\]/ $max = $2 if ($2 > $max); "[$1]"/ge; +s/~\[(\*,\_(\d+),[^,]+(,([^,]+))?)~\]/ _validate($1, $2, $max, $min, $param_error)/ge; + return $str if ($param_error); # get the args to be interpolated. my $argsStr = $params->{args} || ""; + # Escape any escapes. + $str =~ s#\\#\\\\#g if ($escape); # escape any escapes + my @args = split( /\s*,\s*/, $argsStr ); # fill omitted args with empty strings @@ -47,6 +64,26 @@ return $result; } +sub _validate { + + #my ( $contents, $number, $max, $min, $param_error ) = @_ + + $_[2] = $_[1] if ( $_[1] > $_[2] ); # Record maximum param number + $_[3] = $_[1] if ( $_[1] < $_[3] ); # Record minimum param number + + if ( $_[1] > 100 ) { + $_[4] = 1; # Set error flag + return +"<span class=\"foswikiAlert\">Excessive parameter number $_[2], MAKETEXT rejected.</span>"; + } + if ( $_[1] < 1 ) { + $_[4] = 1; # Set error flag + return +"<span class=\"foswikiAlert\">Invalid parameter <code>\"$_[0]\"</code>, MAKETEXT rejected.</span>"; + } + return "[$_[0]]"; # Return the complete bracket parameter without escapes +} + 1; __END__ Foswiki - The Free and Open Source Wiki, http://foswiki.org/ ============ ^^^ CUT ^^^ ============= ---++ Action Plan with Timeline * 2012-12-05 - The Locale::Maketext vulnerability was discussed on the Perl5Porters email list, triggered review of Foswiki code. * 2012-12-05 - Patched version (1.23) of Locale::Maketext is released. * 2012-12-08 - The [_999999] DoS issue identified and sent to foswiki security list. * 2012-12-09 - The "remote execution" vulnerability in Locale::Maketext was confirmed on Foswiki. * 2012-12-09 - Requested the CVE from cve-assign () mitre org * 2012-12-09 - TWiki notified of the Vulnerability. * 2012-12-10 - Developer fixes code (George Clark) and security team validates the fixes. * 2012-12-10 - Extensions.PatchItem12285Contrib released for Foswiki 1.1.x * 2012-12-10 - Security team creates advisory with hotfix. Announcement delayed for coordination with TWiki (George Clark) * 2012-12-12 - Updated Debian packages released (Sven Dowideit) * 2012-12-12 - Send alert to foswiki-announce and foswiki-discuss mailing lists ( ) * 2012-12-14 - Publish advisory in Support web and update all related topics ( ) * 2012-12-14 - Reference to public advisory on Download page and Known Issues ( ) * 2012-xx-xx - Release Manager builds patch release ( ) * 2012-xx-xx - Issue a public security advisory (vuln () secunia com, cert () cert org, bugs () securitytracker com, full-disclosure () lists netsys com, vulnwatch () vulnwatch org) ( )